Financing Arrangements (Narrative) (Details) - USD ($) | Apr. 22, 2016 | Jul. 31, 2014 | Mar. 31, 2016 | Oct. 21, 2015 | Aug. 13, 2015 | Mar. 12, 2015 | Oct. 23, 2014 |
Maximum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Capital lease obligations | | | | | $ 50,000,000 | | |
The Amended Credit Agreement | Revolving credit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | | $ 230,000,000 | | | | | |
Term of debt instrument | | 7 years | | | | | |
Inventory advance rate percentage | | | | | | | 50.00% |
The Amended Credit Agreement | Revolving Credit Facility, Canadian Sub-Limit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | | $ 35,000,000 | | | | | |
The Amended Credit Agreement | Revolving Credit Facility, European Sub-Limit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | | $ 25,000,000 | | | | | |
The Amended Credit Agreement | LIBOR | Revolving credit | Minimum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 1.50% | | | | | |
The Amended Credit Agreement | LIBOR | Revolving credit | Maximum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 2.50% | | | | | |
The Amended Credit Agreement | LIBOR | Term Loan | Minimum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 2.00% | | | | | |
The Amended Credit Agreement | LIBOR | Term Loan | Maximum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 3.00% | | | | | |
The Amended Credit Agreement | Prime lending rate | Revolving credit | Minimum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | (0.25%) | | | | | |
The Amended Credit Agreement | Prime lending rate | Revolving credit | Maximum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | (1.25%) | | | | | |
The Amended Credit Agreement | Prime lending rate | Term Loan | Minimum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | (0.75%) | | | | | |
The Amended Credit Agreement | Prime lending rate | Term Loan | Maximum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 0.25% | | | | | |
The Amended Credit Agreement | Canadian deposit offered rate | Revolving Credit Facility, Canadian Sub-Limit | Minimum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 1.50% | | | | | |
The Amended Credit Agreement | Canadian deposit offered rate | Revolving Credit Facility, Canadian Sub-Limit | Maximum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 2.50% | | | | | |
The Amended Credit Agreement | Canadian prime lending rate | Revolving Credit Facility, Canadian Sub-Limit | Minimum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 0.00% | | | | | |
The Amended Credit Agreement | Canadian prime lending rate | Revolving Credit Facility, Canadian Sub-Limit | Maximum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 1.00% | | | | | |
The Amended Credit Agreement | US base rate | Revolving Credit Facility, Canadian Sub-Limit | Minimum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 0.00% | | | | | |
The Amended Credit Agreement | US base rate | Revolving Credit Facility, Canadian Sub-Limit | Maximum | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | | 1.00% | | | | | |
Amendment No. 1 to the Amended Credit Agreement | Revolving credit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | | | | | | $ 275,000,000 | |
Amendment No. 1 to the Amended Credit Agreement | Term Loan | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Amount drawn | | | $ 26,700,000 | | | | |
Southwest Steel Processing LLC | Arkansas Development Finance Authority | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | | | | $ 11,000,000 | | | |
Amount drawn | | | 0 | | | | |
Machinery and Equipment | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Capital lease obligations | | | $ 17,800,000 | | | | |
Subsequent Event | The Amended Credit Agreement | Revolving credit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Inventory advance rate percentage | 65.00% | | | | | | |
Subsequent Event | Amendment No. 1 to the Amended Credit Agreement | Revolving credit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | $ 300,000,000 | | | | | | |
Amount drawn | $ 35,000,000 | | | | | | |
Inventory advance rate percentage to be reduced to | 50.00% | | | | | | |
Term over which inventory advance rate percentage reduces | 36 months | | | | | | |
Term over which basis spread on variable interest rate reduces | 36 months | | | | | | |
Subsequent Event | Amendment No. 1 to the Amended Credit Agreement | Revolving Credit Facility, Canadian Sub-Limit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | $ 35,000,000 | | | | | | |
Subsequent Event | Amendment No. 1 to the Amended Credit Agreement | Revolving Credit Facility, European Sub-Limit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | 25,000,000 | | | | | | |
Subsequent Event | Amendment No. 1 to the Amended Credit Agreement | Term Loan | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Maximum borrowing capacity | $ 35,000,000 | | | | | | |
Subsequent Event | Amendment No. 1 to the Amended Credit Agreement | LIBOR | Revolving credit | | | | | | | |
Line of Credit Facility [Line Items] | | | | | | | |
Basis spread on variable interest rate - plus (minus) | 3.50% | | | | | | |